Bridge Health Monitoring Tool Enabled Condition-Based Inspections Instead of Time-Based Inspections To Reduce Unnecessary Road Closures and Lower Inspection Costs.
The Bridge Rapid Assessment Center for Extreme Events (BRACE2) Platform was Piloted and Implemented Across 22 Bridges in California to Support Timely and Informed Decision-Making About Bridge Safety.
Statewide, California, United States
BRACE²: Bridge Rapid Assessment Center for Extreme Events Phase I Final Report
Summary Information
The BRACE2 health monitoring platform was developed to support timely and informed decision-making about bridge safety. Its goal was to bridge the gap between decision-makers, engineers, and researchers by providing accurate structural health assessments, particularly after events like earthquakes or accidents. The platform was piloted in California, originally targeting five bridges but later expanded to monitor 22 bridges. The platform integrated with existing infrastructure databases, such as the National Bridge Inventory, and had partnerships with agencies such as the California Geological Survey (CGS), which provided real-time seismic data. BRACE2 included four core elements: assets (i.e., bridge inventory), predictors (e.g., structural analysis models using finite element methods), events (e.g., incidents on happening on a bridge in the inventory), and metrics (quantitative indicators of structural health, such as stiffness or ductility, tailored for decision-making). The platform involved functionalities that allowed real-time data ingestion and communication, and processed and streamed sensor data to the platform within about one minute.
METHODOLOGY
The BRACE2 system automatically generated evaluation reports after seismic events by integrating structural models and sensor data to produce metrics relevant for decision-makers. Evaluations were triggered by seismic activity and computed through a mix of physics-based and data-driven predictors. The evaluation outputs included acceleration, drift, and component damage metrics visualized alongside model renderings and sensor layouts. Each evaluation linked a specific seismic event in the state’s database to a specific bridge asset, allowing for rapid health assessment. Evaluations included full assessments for “full digital twins” (e.g., bridges with extensive real-time instrumentation), and partial assessments for “partial digital twins” (e.g., bridges with limited or event-triggered data). The BRACE2 tool utilized real-time seismic sensor data, generated data from the predictors, traffic data, and bridge metadata from the state and national databases.
FINDINGS
- Enabled condition-based inspections instead of time-based inspections. Inspections were triggered by actual structural response data from seismic events, not arbitrary time intervals, allowing agencies to inspect only when needed.
- Reduced unnecessary bridge closures. Real-time structural metrics helped determine whether a bridge was safe to remain open, reducing precautionary closures that disrupt traffic and incur detour costs.
- Improved efficiency in inspection resource allocation. BRACE2 allowed agencies to focus limited inspection crews and funds on assets that exhibited real structural changes or damage indicators, avoiding broad, low-priority field deployments.
- Avoided costly overdesign or unnecessary repairs. Measured strain and displacement data were used to determine if actual bridge loads were below design assumptions, preventing costly retrofits or restrictions.
- Overall, BRACE2 improved cost-effectiveness by enabling targeted, data-driven inspection and maintenance, reducing both the frequency and duration of road closures, and helping agencies deploy resources only where needed.
